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No Model.)

E. V, GARDNER-- MANUPAGTURE lor WHITE LEAD.

l No. 359,552. Patented Mar. 15, 1887.

. j WM JW M5/g5@ UNITED STATES PATENT OEETQE.,

EDVARD V. GARDNER, OF LONDON, COUNTY OF MIDDLESEX, ENGLAND.

`MANUFACTURE OF WHITE LEAD.

SPECIFICATION forming part of Letters Patent No. 359,352, dated March l5, 1887.

pplicalion led February 12,1883. Serial No. 84,793. (No model.) Patented in England February l5, 1882, No. 731,

invented certain new and useful Improvements in the Manufacture of White Lead, (for which I have obtained Letters Patent in Great Britain,No. 73l,dated February l5, 1882,) of which the following is a specification.

This invention consists in certain methods of treating blue lead so as to convert it into whiteleachwhether the process be carried out in closed or open chambers or spaces.

The said improvements refenparticularl y,to the preparation of the blue lead to be convertedinto whitelead,and toimproved methods of bringing the various materials employed to act and react on each other at certain temperatures and certain conditions of humidity and dryness; also, toimproved methods of arranging the lead to be converted so as to form, in arrangement with other bodies to which it is related in electrical affinity, an electrical combination, and exposing the lead and such other bodies to the action of chemical agents adapted to produce an electric current, as described. 4

I prefer, for carrying out my invention, to employ a closed but not an air-tight chamber, which is ventilated or relieved so as to enable the incoming gasesand vapors to enter it Without hinderance, and to escape by means of an exit valve or channel.

In carrying this invention into effect I first prepare the convertingchamber and dispose of all the necessary arrangements for charging it with the blue lead, which, beforeconversion, is submitted to the action of free acetic acid or nitric acid, or avmixture of these and salts of lead and Water. This step of the process, as has already been indicated, ispreparatory to that of conversion, and is carried out by immersing the lead for a few minutes in a trough containing Water holding in solution a salt of lead and free acetic acid or free nitric acid, or a mixture of these .two acids. This treatment prepares the surface of the lead and expedites the process of conversion. The liquid bath just mentioned having been prepared in a tank containing a slab of stone, slate, or iron, I melt the lead in any convenient manner and obtain the molten metal at'a low red heat. I- then pour the same from a height of about four to six feet into the iiuid contained in the tank or vessel,in such a manner that it shall fall through the iiuid onto the said slab, which may be inclined, as Will be' Well understood, so that the metal on coming into contact therewith is free to pass off into the duid; 0r the slab may be arranged to rotate, or the lead may be taken off by Scrapers. Blue lead is thus granulated and brought into a spongied condition, and is also prepared for the process of conversion. Although I find the said solutions suitable for spongifying and preparing the lead in the manner lastly described,

I in some cases substitute water therefor and spongify the lead in a similar manner.

The lead, by preference, for some operations, prepared and spongitied as hereinbefore described, is arranged on the trays or frames or on other supports, which, when loaded, are' lifted bodily by a hoist and let down through the top ofthe converting-chamber to their places Within the same; 0r the lead is introduced in any other convenient Way. The lead is arranged on the said trays, frames, or other supports in any convenient manner, so as to form, with other suitable substances, an electrical combination, and so as to allow the gases and vapors, hereinafter described, to surround the lead in such a manner as to prevent any direct eddies or currents being formed on meeting the substances Within the chamber. I prefer framed supports, similar to a dinner-wagon, for holding the lead' and other materials. 'Ihe said shelves, trays, or other supports are formed so as to have their bottom surfaces made of or covered with artiicial graphite or hard coke, such as is used for electrical plates in batteries, or of plates or blocks made of a composition of coke or coal With. anthracite clay and bitumen, or of coke and free-burning coal in certain proportions, as Will be Well understood, prepared and baked; or I employ plates of graphite, hard coke, platinum, tin, or of carbonized and platinized or similar materials as are in similar electrical relations to lead.

In some cases the lead is placed on or in shelves or trays, so as to bein such conjunction with pieces of carbon or any of the said IOC materials as to form an electrical arrangement, and in this case the bottoms of the supports may be formed of any convenient material.

Instead of employing or in addition 'to the employment of carbon or other materials which generate, in conjunction with the lead, electrical currents, I sometimes bring ozonized air or oxygen into contact with the lead, andin some cases the air or oxygen ozonized within the chamber, by passing electric discharges through the same; and thus I electrify the materials and increase their chemical action one upon another. Although the said methods will be found convenient, I do not coniine this part of my invention to the precise details therein described, as many modifications thereof will be found equally suitable for the purpose.

Vhen the convertirig-chamber is thus arranged and furnished with its proper charge of blue lead, it is closed and then heated by suitable heating apparatus until the temperature within the chamber rises to 120 Fahrenheit, or thereabout; and it is kept at that temperature for three or four hours-in fact until the whole of the contents of the chamber are of one uniform temperature. This having been effected, the vapors of a mixture of acetic acid and nitric acid, with or without oxygen, are supplied at a proper heat and passed into the converti iig-chamber bysupply-pipes. The supply of a mixture of acetic acid and nitric acid, watery vapor, and air, and so on, as hereinbefore described, is kept up at a moderate rate. The temperature ofthe chamber must not be allowed to fall below 110 Fahrenheit, nor to amount to above 125 Fahrenheit, which is the fittest stage. The heat can be readily governed and regulated. The hot vapors and gases coming into the converting-chamber tend to preserve the heat of its contents, or even to raise their temperature, so that it may be required to reduce the action of the heating apparatus and to so lessen the supply of the hot gases and vapors as to diminish the general temperature of the same within the converting-chamber, and to preserve them at about 120 Fahrenheit; and this is continued for twenty four hours. Should electrical discharges be employed in place of electrical combination within the chamber, as hereinbefore referred to, in order to accelerate the process, they are passed from any convenient surce and by suitable means through the substances engaged in converting blue lead into white lead-such as air, oxygen, and so on-before they enter the converting-chamber as they are passed through the atmosphere of the mixed gases and vapors within the converting-chamber, such electrical discharges being made oeeasionally, so as to excite and keep up the chemical energy of the materials within the chamber in their action on each other during the process of conversion.

When the lead is arranged so as to be brought into action with carbon, platinum, tin, platinized materials, or some such electro-negative as will, with the lead, form a galvano-electric combination, as hereinbefore described, all necessity for the employment of electrical discharges is dispensed with. 'Within the chamber a moist misty atmosphere is the best, and the same can always be easily secured and preserved at the proper degree of humidity and temperature by a due regulation of the heating arrangement and of the evaporation of the gases and vapors into the converting-chamber. After twenty-fourhours the heat may be allowed to rise, but not to exceed about 130 Fahrenheit, provided that the atmosphere within the converting-chamber is not allowed to become dry and thirsty; but 125 Fahrenheit is the most safe and sure heat. This seeond stage is continued for another period of twenty-four hours. The temperature may now vary between 120 and 135 Fahrenheit, and must not be allowed to get above 135, nor much below 120, or the material will suffer. After the expiration of the said period of forty-eight hours carbonio acid or carbonic acid mixed with air or oxygen and heated to a proper temperature, as will be well understood, is passed into the converting-chamber and distributed therein by suitable apparatus. This supply of earbonic acid or of that gas and air or oxygen is, when desired, ozonized and is continued for two' hours, the supply of the acid vapor and air or oxygen being continued through the same period. After two hours the carbonio-acidgas supply is shut off, the supply of vapors and aqueous vapor and air or oxygen being continued through the same period. After two hours the earbonic-acid-gas supply is shut ofi" and the supply of acid vapors and aqueous vapor and air or oxygen is continued, as before, for another four hours, and so on, the carbonic-aci( gas heilig supplied, as before stated, for two hours in every six hours, the acid vapors and aqueous vapor and air or oxygen being continued the whole time. As the process of formation of white lead advances, in about four or five days effervescence of the surface of the lead will be observed, or exfoliation of the lead will commence. The supply of carbonic acid is to he increased two hours in every four hours, or to four hours in every six hours, and the continuous supply of acid vapors and aqueous vapor and air or oxygen may be increased in quantity, with due observation of the precautions already mentioned, saving that as the incrustation of White lead thickens on the surface of the lead the temperature should be preserved at about 130 to 135 Fahrenheit. In seven to fourteen days or thereabout the process will be completed and the blue lead will be entirely, or for the greater part, converted into white lead.

Although in some instances I prefer this mode of treatment in the process of making white lead from blue lead, I do not confine this invention to the exact periods of time above mentioned, or to any set period. I nd that with blue lead prepared and spongied, as hereinbefore described, I can accomplish the IIO f process of conversion in much less time than seven or fourteen days. I iind that while the periods of time above mentioned may be advantageously observed in treating spongitied lead, in other cases, such as operating with castings, they may be varied.

It will be readily understood that it is not desired to confine the invention to the exact periods of time` hereinbefore stated, as with the spongy 7 lead prepared as hereinbefore described much less time than from seven to fourteen days is required.

When the conversion of the contents of the converting-chamber is completed, they are transferred to a grinding apparatus, or they may be treated in any desired manner. When it is desired to grind the white lead, a comminuting apparatus, which is constructed in the following manner, may be employed, reference being had to the accompanying drawings, in which- Figure l isa vertical section of the comminuting apparatus. Fig. 2 is a modification of the same. l

In the drawings, A B C D is an outer casing, inclosing the whole apparatus and preventing the escape of any particles of the material under treatment, and in said casing are placed two cylinders, F F', of any suitable form, which are pierced with holes or perforations, or made up so as to have a series of longitudinal spaces or apertures. When two cylinders are employed, although not always the case, the cylinder Fhas the spaces made closer together than the cylinder F. The spaces or apertures of the cylinders are covered with wire-netting or wire-gauze, so as to form a sieve through which the comminutedsubstance falls. Balls of metal, wood, or stone areplaced in the cylinder to assist the pounding action of the material.

E is the exterior hopper, closed by doors 1 and 2, and E is the interior hopper.

The material to be pulveri'zed is placed first` in hopper E and passes into the cylinder F, through a suitable door, which is then closed. The cylinder is then caused to revolve,and beloW it, or each cylinder, if two are employed,

is placed a screen or sieve, G, into which the substance from the cylinder or cylinders falls and is sifted. The sieves receive a jolting `motion through the medium of a goggle or other suitable mechanism, aud they are inclined so as to deliver the core, which cannot pass through the meshes, to a suitable opening in the outer frame; When one cylinder only is employed, this is all that is required; but when two cylinders and two sieves are used a second hopper, E', receives the material passing from the first sieve and conducts it to the second cylinder, F, where it is treated in a similar' manner as it was in the first cylinder. The hopper E is provided with a door, H, which is opened from without, as is also the door of the cylinder F. A receptacle, I, receives the powdered white lead. In the modication shown in Fig. 2the cylinder A" revolves on suitable axis, and is driven by the pulley B. One end of the axis is hollow and has a hopper-tube, c, fitted into it.- rIhe material is introduced through the hopper into the tube, and is then pushed by a piston, D', into the interior of the cylinder A. Suitable balls are then placed into the cylinder A', which has on its face openings E E, covered with gratings or gauze for sifting the contents of the cylinder.

Grinding or comminuting in water can be effected in any of these apparatuses, by allowing water to flow in at the top/of the ease into the cylinder through the gratings or gauze as the cylinder revolves, and to How out into troughs beneath.

Hitherto the gases and vapors of acetic or nitric acid, or ot" either of those acids mixed with Water, have been employed for the conversion of blue lead into white lead. I have discovered that the said process of conversion is more effectually and rapidly effected by the employment of a mixture of the gases and vapors of acetic acid and nitric acid together with air and carbon gases, and I add Water or watery vapor to the said gases andvapors. These gases and vapors act on the lead in the process of conversion, and a perfectly amorphous dense white and soft incrustation of white lead is obtained in an expeditious and convenient manner. p

I arrange the lead within the convertingchamber in connection with any suitable electro-negative to lead, such as carbon and tin, the consequences being that ou the admission of the gases and vapors to the chamber the whole of its contents become excited by electrical action, and the process of conversion is thereby greatly facilitated.

In order to increase the activity of the gases and` vapors employed within the convertingchamber,I submit them to the action of electrical discharges derived from any suitable source, either before they enter or after they have entered the chamber, and thus enhance the effect of the gases and vapors in converting the lead into white lead. e

As already stated heretofore, the electrical discharges within the converting-chamber may be produced by any known means-such, for eXample,asaLeyden jar-orany device whereby dynamic electricity may be stored for mechanical or other purposes.

What I claim as my invention is-n l. The process described for the manufacture of white lead from blue lead, consisting in subjecting the blue lead to the action of a mixture of free, acetic or nitric acid with salts of lead and Water, then subjecting the lead in a converting-chamber to the action of the vapors of a mixture of acetic and nitric acids and Water with carbonio-acid gas, said acid and watery vapors and gas being introduced simultaneously and the interior of the chamber being retained at the temperature speciiied, substantially as set forth.

2. In the manufacture of white lead from ICO blue lead, the within-described method of facilitating and expediting the corrosion of the blue lead, which consists in placing within the converting-chamber said bluelead in electrical connection with an electro-negative to such lead, such as carbon or tin, or some other electro-negative to lead, and then submitting the same to the action ofthe converting agents, substantially as described.

3. In the process of manufacturing white lead, the method of increasing or exciting the activity of the gases or vapors employed as the converting agents, consisting iu submitting them to the action of electrical discharges when about to act upon or while acting upon the metallic lead, substantially as herein set forth.

4. The within-described process of convert ing blue lead into white lead, consisting in, first, preparing the surface of the blue lead b y submitting it to the action of a mixture of free acetic or free nitric acid and salts of lead and water, or a mixture of these acids and salts oi' lead and Water, as described, and, secondly, in

arranging the lead so prepared in the converting-chamber on suitable supports and in connection with electro-negatives of lead, such as carbon or tin, and so arranged submitting them to the action of the vapors of a mixture of acetic and nitric acids and Water or watery vapor and earbonic-acid gas and air or oXygen, substantially as described.

5. In the process of converting blue lead into white lead, the method herein described of increasing the activity of the converting agents, said method consisting in forming within a suitable chamber a mixture of acid and watery vapors, carbonio-acid gas, and air or oxygen, and subjecting the same to the action of electrical discharges derived from any convenient source, substantially as described.

EDVD. V. GARDNER.

\Vitnesses:

Gao. V. VAUGHAN,

67 Chancery Lane, London. T. C. MEARING,

33 Sidmouh Sfrcc, Loudon. 

